After four solid days eating nothing but Soylent, Saturday dawned. I awoke feeling about the same as I had the day before and the day before that. I didn't feel particularly incredible, but I didn't feel bad either. Coffee led to my morning Soylent, which was from yesterday's blue batch. I had plenty left to get me through the day—it looked like about half the pitcher remained.

I had a half-formed plan in my mind though. Perhaps, just perhaps, I could stretch this pitcher through to dinner. Because if I could make this bit of Soylent last all day, I'd have one full, unopened, shiny plastic pouch left. My friends and I were all supposed to gather at Matt's house for Labor Day, and rather than showing up with steak and hamburgers to grill—well, I could show up with Soylent. I could make all of them drink it. It would be a Very Soylent Labor Day.

The final countdown

As much as I'd like to have some grand crazy story to wrap up my final day of Soylenting, things were uneventful. My poo continued to look like a preschooler's art project, but that's more because of my dabbling with food coloring than anything the actual Soylent was doing. The gas pretty much disappeared. The chalkiness still got to me, but I started adding more and more water to my mug-sized servings, and that cut the chalk right out.

I didn't bleed out of all of my orifices, I didn't go into hyper- or hypoglycemic shock, and I didn't combust. I finished the pitcher for dinner, smacked my lips, and tossed all my Soylent implements into the dishwasher. Later that evening, I ate my first piece of food in five days: a banana. (It was late and I wasn't super hungry.)

Returning to solid food was not earth shattering. I didn't experience any kind of food-related tastegasm, and my jaws didn't ache with release from chewing. It was a banana. It tasted like banana and then I went to sleep.

On Sunday, I woke up and had my usual bowl of oat bran for breakfast, because when you're 35 you start having to eat things like oat bran because that's about when your body starts to betray you by getting old. It tasted fine.

Anticlimax

I kind of feel like I'm failing to deliver on the Soylent conclusion, because the narrative here doesn't really follow the traditional dramatic structure. There was rising action and a bit of falling action, but there was no real finale and no real denouement. Soylent worked and my body was able to handle it, initial overeating issues aside. I was able to take my normal 5k runs on it. Aside from adaptation gas, it didn't do weird things to me.

As the five days stretched on, I didn't feel bad. I didn't feel powerful longings for solid food. There was no overwhelming desire to cheat and buy a cheeseburger just to have something to sink my teeth into. In fact, I ate pretty lightly for most of Sunday too—rather than dump a whole bunch of crazy weekend food into my body, I gave it a day to adjust again. Switching back to "normal" food didn't bring with it any adaptation issues: no dizziness, no gas as my gut bacteria shifted gears again. Nothing.

From a weight loss perspective, the results don't seem statistically significant. I weighed myself at the same time and at the same point in my morning routine every day, and I lost 2.2 lbs (about 1 kg) over the five days. I've fluctuated more than that day-to-day from just eating normal food and exercising, though, so saying that I lost weight on Soylent is correct but not particularly meaningful. Based on my consumption rate, though, I'd figure that eating nothing but Soylent over several weeks would result in weight loss—of course, so would just about any nutritionally balanced food regime.

So, the experiment was a success, and I lived to tell the tale.

Feeding Rob Rhinehart some Ars commenter questions

Soylent creator Rob Rhinehart was kind enough to sit down and talk with me for a bit on the Ars Soylent experience. He answered some of the questions that came up in the comments over the past several days.

The one I most wanted him to elaborate on was on the why of it all. The comments on the past pieces in this series have been brimming with folks who can't (or won't, perhaps) see the point of Soylent. Whether it's because they love cooking too much, or they can't understand why someone would drink a nutrient slurry in place of food, some people were not at all on board.

"Soylent is supposed to be like an ultimate staple meal," began Rhinehart. "When you think about food, a lot of people immediately jump to the best aspects, which are great—eating for recreation, eating with people. This is an important part of life, and food is intimately tied with culture and tradition."

But not every meal is artisanal, fresh, and healthy; Soylent aims to fill in those gaps like a utility. "People will talk about beer and wine and gourmet coffee, but most of the time they're drinking water. By focusing on Soylent as a staple, fool-proof meal, this could do a lot more for health than some new recipe based on lettuce or something."

The name

The name itself, "Soylent," has drawn fire—but that's part of the reason why Rhinehart chose the name in the first place. "For food, a lot of people tend to react quickly and not give it a lot of analysis. Piquing curiosity is very important here, and giving the product some kind of flashy marketing name would kind of—people would miss it quickly. But the name 'Soylent' is really good for encouraging further discussion and thought. Clearly, I'm wanting someone to investigate it a little deeper if I'm calling it 'Soylent.' It doesn't seem very marketable!" The name serves several purposes—it catches the interest of geeks as almost an inside joke ("IT'S MADE OF PEOPLE!"), and it's remarkably sticky.

Hasn't this been done before?

This, though, leads into another topic that readers commented on repeatedly: Soylent's originality, or its perceived lack thereof. Meal replacement products aren't anything terribly new, and there are products both in the consumer space and also in the medical and healthcare space that can be substituted for solid food. Soylent is billing itself as a revolutionary product. Is it?

"From the consumer standpoint, those things aren't designed to be sustainable or really even that healthy," Rhinehart said, referring to things like Carnation Instant Breakfast and Slim Fast and other common off-the-shelf meal replacement shake-style drinks. "They're certainly not something you'd want to run your body off of—a lot of fructose, simple sugars, and by calorie it's really expensive. We've reached a point of calories-per-dollar and sustainability and nutrition where we're really trying to compete with groceries."

On the medical side, products like Jevity and Nestlé's entire line of liquid tube feeding products are in a separate league from Soylent. "We're not making any medical claims, other than it being safe for consumption," clarified Rhinehart. Additionally, from a perspective of calories per dollar, both the consumer and the medical liquid nutrition products are outside of what Rhinehart wants to target for Soylent. Rhinehart wants Soylent "to compete with rice and beans," he explained. "The routine meals that a lot of people are eating—that's what we want to compete with, especially if we can displace fast food."

Processed ingredients

The stigma carried by Soylent's processed ingredients also came up several times. Several readers twigged to the fact that Soylent is made of highly processed substances rather than an organic blend of things. "People who demonize food processing don't really understand what's going on there," clarified Rhinehart. "Food processing gives us fortified foods. It makes food cheaper. It allows people with allergies or dietary restrictions to eat better. It's a useful innovation, but it has been misused by many food companies—you can use it to make something that is very experiential but perhaps not very healthy, and unfortunately, that's what a lot of food companies design for. I think we can use this technology to make a very easy, nutritious type of food—cost effective and ubiquitous, and something that doesn't spoil."

Rhinehart continued, "It's important to realize that these nutrients, these chemicals—they're all the same. Whether your calcium comes from milk from a cow you own yourself, or from some industrial process, it's all the same for your body, as long as it's in a bioavailable form."

Taste, texture, testing

As Soylent barrels toward the market, there are still minor tweaks to the formula to be made, but the nutrition and taste components are mostly locked. The remaining adjustments are more to make Soylent manufacturable at scale than anything else. I brought up the chalkiness that I had such a hard time with, and Rhinehart acknowledged that as a "bug" with the formula. They are working around by altering the particle size of the rice protein.

However, no small subset of readers was concerned that Soylent would become widely available without an extensive test regime to validate Rhinehart's claims that it's a safe and healthy product; according to Rhinehart, none is necessary. Every one of the individual components in Soylent has already undergone FDA testing, which Rhinehart is quick to point out. "Of course something like this is safe for consumption. All of the ingredients are very well-vetted to be safe. Every one of them has been tested individually, and there are no conformational or chemical changes undergone by blending them together with water, and it's really unnecessary to test the mixture for, say, FDA GRAS testing." There are other tests to be done as part of the manufacturing process—ensuring the product is free of microbial contaminants or heavy metals for example—but that Soylent is safe for human consumption seems beyond reproach.

"Again, we're not making any medical claims here," he explained. "Soylent is not a drug, basically, and we're not testing on that level. We are designing a number of studies to catalog the health benefits, though—a lot of people are seeing reduction in triglycerides or cholesterol; others are seeing improved performance or sleep. Some things are more difficult to quantify than others, but I think we can show a lot of clearly objective health benefits in incorporating this into one's diet."

Soylenting the world

There are currently six people working on Soylent, including Rhinehart, and the company is focused on bringing the product to market. However, the plans don't stop there. Rhinehart wants to target a per diem cost for Soylent of about $5 per day, which is affordable to most and which also leaves room for Soylent to be profitable. However, the intent is also there to keep Soylent libre—once finalized, the formula will be freely available, and folks can make their own.

Indeed, Soylent already has a tremendous and healthy DIY community producing and eating their own pre-release versions. After release, Rhinehart doesn't mind if people continue making their own or pay a bit more to the Soylent company for the convenience of having pre-made Soylent shipped to them directly.

Soylent has struck a solid cord in the DIY and geek set, in no small part because of that encouragement to tinker. Cooking is something that a lot of engineering geeks have difficulty with, because even easy recipes contain "soft" directions—rather than dealing with precise quantities and measurements and conditions, they're often a lot more analog in their descriptions and conventions. Soylent, on the other hand, is solidly digital—mix precisely so much of ingredient A to receive nutrient A, mix precisely so much of ingredient B for nutrient B, then shake and consume. Rhinehart calls it "cooking at a lower level" and went on to summarize the geek appeal of Soylent. "Food is hardware," he said. "It's something that can be designed and optimized."

After developing a sustainable US business for Soylent, the next step is to attempt to commoditize nutrition outside of the first world. Indeed, commenters have picked up the commonalities between Soylent and universal nutrition food Plumpy'nut, which is often used in undeveloped areas to supplement diets. In fact, Rhinehart credits the licensing and production issues behind Plumpy'nut as one of the big inspirations behind not patenting Soylent and keeping it libre. He noted that when the time comes, Soylent would work with existing NGOs and governments with food distribution channels to attempt to get Soylent out to areas that need nutrition. One potential obstacle to overcome would be Soylent's dependence on water to become edible (something Plumpy'nut does not need), but Rhinehart stated that they could potentially distribute water purification gear with Soylent.

Soylenting my friends

But I wasn't concerned with getting Soylent to the third world on Labor Day; I wanted to get it in front of my hungry friends. I showed up to Matt's house bearing not ground beef and steaks, but rather a pitcher and a crinkly plastic bag. However, like a group of cats exposed to a new box, curiosity quickly overcame everyone, and I was peppered with questions as I mixed up a batch.

By far the most curious was my buddy BJ, who's probably one of the healthiest people I know (and also the inspiration behind my own running habit). He was the first one to hold his hand out, and he pronounced the Soylent to be "perfectly cromulent."

However, his reaction was by far the most positive. No one else seemed to like Soylent's flavorless flavor or its chalkiness. Their reactions were priceless.

Enlarge/ Reaction shot of some of the group immediately after imbibing their first Soylent.

Lee Hutchinson

Everyone mentioned how they'd drink Soylent over death, but they wouldn't eat it given a choice for anything else. There was much laughter and then we proceeded to cook up the BBQ, crack open the beers, and carry off Labor Day in fine style.

And a curious thing happened. As the day wore on, one by one, every one of my buddies came up to me in various stages of Labor Day food coma drunkenness, and every single one of them looked around, leaned in close, and confided a variation on the same secret.

Rhinehart is quite wrong on one aspect: he feels that no FDA testing needs to take place because they aren't making any medical claims. On the contrary - they are making one very big claim: that you can survive on Soylent without other food. Sure, the ingredients have already been cleared for consumption, but it is a very different thing to say "this isn't going to kill you" vs. "you can live off of only Soylent without any adverse affects".

This is why all cereal ads claim that their cereal is healthy when part of a balanced breakfast.

Thanks for the experiment though. I loved reading about your experiences... well, most of them

This was very useful. I need to do some more research on Soylent. I'm not a foodie, I don't particularly enjoy eating and I always wished for a "space pill" that I can take and be done for a day. Get all my nutrients and not be hungry. I also have trouble staying fit, I gain weight quickly and I am really bad at keeping my calorie intake count. I've been trying to count the calories in food but it's so freaking hard so I'm sure I end up overeating.

I really like the idea of getting a precise amount of nutrients and calories for my body and not worry about overeating.

Rhinehart wants to target a per diem cost for Soylent of about $5 per day, which is affordable to most and which also leaves room for Soylent to be profitable.

that may be affordable to most, but rice and beans (with tomatoes or a multivitamin pill to prevent scurvy) is even cheaper and I think most people would rather have that than a glass of brownish chalky liquid.

at least it's brownish now instead of the old off-white. one of the Gawker guys tried it a few months ago and couldn't stop talking about how much it looked like jizz.

The estimated shelf life is something that I'm very interested in, as well.

Not only do I not like cooking (the analog-ness of it makes half of what I make not come out right at all), but I hate shopping, too. So if I could pick up a case of this stuff and cut down the number of shopping trips I make, that would be awesome.

I don't know if I could actually move onto this stuff and not eat, though it seems pretty much a requirement for any survival kit or disaster kit.

What's the shelf life of a bag? How often do you need to replace it if you don't actually use it?

No exact answer on that as I was curious about the same thing and went looking for an answer. So far the rough estimates are about 1 year unopened, less after opening, and a few days after being blended. At least in part it will depend on the final formula so I'm not sure anyone can know for sure until that is decided.

This was very useful. I need to do some more research on Soylent. I'm not a foodie, I don't particularly enjoy eating and I always wished for a "space pill" that I can take and be done for a day. Get all my nutrients and not be hungry. I also have trouble staying fit, I gain weight quickly and I am really bad at keeping my calorie intake count. I've been trying to count the calories in food but it's so freaking hard so I'm sure I end up overeating.

I really like the idea of getting a precise amount of nutrients and calories for my body and not worry about overeating.

Not overeating is all about impulse control, that's what you want to work on first .

Running, sticking to a regular sleeping schedule and meditating all increase impulse control, pick whichever combination suits you. All three being the ideal (I'm working on the second and will incorporate the other two as I progress).

This said, switching to soylent probably would help too because its high water content seems to increase the feeling of satiety. As Lee's experience seems to indicate, you cannot easily ingest too much Soylent because it satiates you very quickly, that could be an efficient way to fight overeating impulses .

Rhinehart wants to target a per diem cost for Soylent of about $5 per day, which is affordable to most and which also leaves room for Soylent to be profitable.

that may be affordable to most, but rice and beans (with tomatoes or a multivitamin pill to prevent scurvy) is even cheaper and I think most people would rather have that than a glass of brownish chalky liquid.

I wouldn't. I'd prefer to drink a brownish, chalky liquid that I could add a dash of flavoring to than to cook and eat rice and beans.

Granted, I'd prefer something more like actual food than a liquid. But I don't consider rice and beans an improvement over Soylent.

Excellent series, I'm really interested in trying this once it's been in the market a while.

Too often my morning meal is grabbing a granola bar before you head out the door and grab something on the go for lunch - if I could get a filling meal out of a bottle in the fridge that does me till suppertime it would be a godsend.

I've started to swim an hour or two after work every day recently. After that I'm hungry and among the places still open at all is a fast food chain directly next to the swimming bath. Let's face it, if I come home at 10-12pm, yes, it's that project kind of thing, I won't cook anymore. It seems not worth it for one person and my GF won't wait with her dinner that long. I also understand that she is not willing to stand next to me for 40 minutes in the kitchen at that time.

This is what I'd like to have soylent for.

I have no desire for fancy food and great taste and I don't need any social experience here, the latter is breakfast for me. I am just hungry and want something that gets me pleasantly filled without being overly expensive or costing me a lot of time. So just mixing some powder into a bottle of water and drinking that on my way home would be cool to have.

Is it good food? Rather not.Is it better than burgers and fries? Probably yes.

It'd be nice to see them experiment with different flavors. Stuff like banana, strawberry, and blueberry, and chocolate shouldn't be that hard to come up with. I'd also be curious to see if they can increase the nutritional density; from what I've been able to tell the "three meal" serving is both quite a lot in the bag, and mixes up to quite a lot of finished product.

I am not surprised to the reaction of your friends upon discovering and trying Soylent, countless studies have shown that humans dread novelty and change and it's only normal that something that goes inside your body is looked upon even more skeptically. Moreover, many people have developed acquired likes and dislikes for various foods so they will be doubly careful (Lee, congratulations to your friend Matt by the way, it's courageous for a self proclaimed picky eater to push one's envelope!). I know it took me quite some time to voluntarily disengage all apprehensions I had for various foods when as a teenager I decided to try everything objectively before deciding I liked it or not but the result was worth it: there is simply no food that I do not like. And although I still favour some tastes over others I can pick a menu without fear of getting something that is not to my tastes.

Which is why I will gladly give Soylent a try as soon as it is available for the masses. I am even curious to try the chalkiness texture you mentioned and I wonder if I could like it as well.

An example I like to give to people when I want to show them that most of the time their tastes are simply a rationalization of their habits (and sometimes fears) is propose them to try to plunge a freshly fried Mc Donald's fry into the ice cream of a sundae. The immediate reaction is invariably surprise and disgust and the rationalization that potato and ice cream, sugar and salt, warm and cold, main meal and dessert can not possibly mix. All this being of course completely wrong because many well known recipes do mix these together with great success but we are simply not used to try this with completely common junk food. Humans's ability to rationalize a completely emotional reaction to non conformity is just mind blowing .

Evidently, once they try they realize that it's actually quite good precisely because of the various contrasts. I love how most of them try it once, appreciate it, then refuse vehemently another try as if it was tantamount to changing religion. Of course when you ask them the next time you see them they will admit that they now tend to do it naturally whenever they have fries and a Sundae (which hopefully is not too often).

Lee, did Rhinehart mention packaging in sizes smaller than one day's worth of Soylent? I'm not sure what that does to the pricing model, but I can see great utility in using this as a meal replacement here and there. Having to deal with storing unused powder left in a huge bag (if I were to only need a single serving), while not a deal-breaker, would be an inconvenience added to what is shaping up to be an ultra-convenient product.

What an entertaining series of articles. Thanks so much for doing this.

This *was* an interesting series of articles. But what struck me is the number of people who would subsist on "bachelor chow" instead of prepared or cooked foods. By no means am a gourmand, but I like to eat and every once in a while like to cook. I have no problem with Soylent for subsistence, but that's as far as I would go.

I've started to swim an hour or two after work every day recently. After that I'm hungry and among the places still open at all is a fast food chain directly next to the swimming bath. Let's face it, if I come home at 10-12pm, yes, it's that project kind of thing, I won't cook anymore. It seems not worth it for one person and my GF won't wait with her dinner that long. I also understand that she is not willing to stand next to me for 40 minutes in the kitchen at that time.

This is what I'd like to have soylent for.

I have no desire for fancy food and great taste and I don't need any social experience here, the latter is breakfast for me. I am just hungry and want something that gets me pleasantly filled without being overly expensive or costing me a lot of time. So just mixing some powder into a bottle of water and drinking that on my way home would be cool to have.

Is it good food? Rather not.Is it better than burgers and fries? Probably yes.

Yes, Soylent is probably better both nutritionally and because it seems to satiates you faster than usual meals.

But I am really surprised that you feel the need to eat after exercise. I know quite a lot of people do but I am completely opposite: if I work out for one hour at say 18, once I leave at 19 I won't feel the need to eat until the next day. Exercise completely suppresses my feelings of hunger.

Hopefully Rhinehart is still reading these (at least, I think I saw him chime in previously?):

Is there consideration "single serving" sizes? I mean, I don't think I'd take this over cooking, but I could see stashing some bags in my desk as a quick crunch-time meal, or for when we have to come in for a declaration and dinner is of questionable availability.

From a first-world perspective that seems to be the better use. Aside from college kids, if they could buy it cheaper than Ramen.

This was very useful. I need to do some more research on Soylent. I'm not a foodie, I don't particularly enjoy eating and I always wished for a "space pill" that I can take and be done for a day. Get all my nutrients and not be hungry. I also have trouble staying fit, I gain weight quickly and I am really bad at keeping my calorie intake count. I've been trying to count the calories in food but it's so freaking hard so I'm sure I end up overeating.

I really like the idea of getting a precise amount of nutrients and calories for my body and not worry about overeating.

Not overeating is all about impulse control, that's what you want to work on first .

Running, sticking to a regular sleeping schedule and meditating all increase impulse control, pick whichever combination suits you. All three being the ideal (I'm working on the second and will incorporate the other two as I progress).

This said, switching to soylent probably would help too because its high water content seems to increase the feeling of satiety. As Lee's experience seems to indicate, you cannot easily ingest too much Soylent because it satiates you very quickly, that could be an efficient way to fight overeating impulses .

I've been riding a bike to work, 8 miles each way, pretty much every day for the past 3 years and I can't drop my belly. I just can't figure out how to eat properly, I'm afraid, and something like Soylent would be ideal for me. But there seems to be a lot of controversy surrounding it. I'd really like to see some long term testing, something that goes on for at least a few months.

On serving sizes: the plan once Soylent is widely available is for the mix to be homogenized, so you can scoop out as much (or as little) as you need for single servings. The bags are already resealable.

I am not surprised to the reaction of your friends upon discovering and trying Soylent, countless studies have shown that humans dread novelty and change and it's only normal that something that goes inside your body is looked upon even more skeptically. Moreover, many people have developed acquired likes and dislikes for various foods so they will be doubly careful (Lee, congratulations to your friend Matt by the way, it's courageous for a self proclaimed picky eater to push one's envelope!). I know it took me quite some time to voluntarily disengage all apprehensions I had for various foods when as a teenager I decided to try everything objectively before deciding I liked it or not but the result was worth it: there is simply no food that I do not like. And although I still favour some tastes over others I can pick a menu without fear of getting something that is not to my tastes.

Which is why I will gladly give Soylent a try as soon as it is available for the masses. I am even curious to try the chalkiness texture you mentioned and I wonder if I could like it as well.

An example I like to give to people when I want to show them that most of the time their tastes are simply a rationalization of their habits (and sometimes fears) is propose them to try to plunge a freshly fried Mc Donald's fry into the ice cream of a sundae. The immediate reaction is invariably surprise and disgust and the rationalization that potato and ice cream, sugar and salt, warm and cold, main meal and dessert can not possibly mix. All this being of course completely wrong because many well known recipes do mix these together with great success but we are simply not used to try this with completely common junk food. Humans's ability to rationalize a completely emotional reaction to non conformity is just mind blowing .

Evidently, once they try they realize that it's actually quite good precisely because of the various contrasts. I love how most of them try it once, appreciate it, then refuse vehemently another try as if it was tantamount to changing religion. Of course when you ask them the next time you see them they will admit that they now tend to do it naturally whenever they have fries and a Sundae (which hopefully is not too often).

I wouldn't. I'd prefer to drink a brownish, chalky liquid that I could add a dash of flavoring to than to cook and eat rice and beans.

Granted, I'd prefer something more like actual food than a liquid. But I don't consider rice and beans an improvement over Soylent.

you can add pretty much any kind of meat, sauce, cookable vegetable, or powdered spice to rice and beans without making it super gross. adding anything chunky to Soylent would be disgusting, and I don't think I'd like drinking a liter of liquid that tastes like curry or soy sauce or whatever by itself.

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.